Experimental Study on Performance of High-Performance Concrete Based on Different Fine Aggregate Systems

To advance the adoption of manufactured sand, this study investigated concrete mix designs wherein manufactured sand partially substituted natural river sand and fully replaced fine aggregates. The influences of the water–binder ratio and fly ash content were also examined. Experimental findings indicate that at replacement rates of 50% and 70%, the workability and mechanical properties of mixed sand concrete experienced a decline. The mechanical performance of concrete improved as the water–binder ratio decreased. Additionally, the strength properties of manufactured sand concrete initially increased with higher fly ash content but slightly decreased when fly ash content reached 30%. Nevertheless, all strength metrics still satisfied the design specifications. Thus, the overall performance of high-performance concrete incorporating manufactured sand remains favorable, demonstrating its viability as a full replacement for river sand in concrete production.